Aortic cannula orientation and flow impacts embolic trajectories: computational cardiopulmonary bypass

Perfusion ◽  
2019 ◽  
Vol 35 (5) ◽  
pp. 409-416
Author(s):  
Raymond Ho ◽  
Charles McDonald ◽  
Jo P Pauls ◽  
Zhiyong Li
Keyword(s):  
Cardiopulmonary Bypass ◽  
Numerical Study ◽  
Ascending Aorta ◽  
Brachiocephalic Artery ◽  
Final Position ◽  
Forward Flow ◽  
Aortic Cannula ◽  
Lesser Curvature ◽  
The Impact ◽  
Aortic Branch

Introduction: Emboli events are associated with the aortic cannula insertion and final position in the ascending aorta. However, the impact of subtle changes in aortic cannula movement and flow influencing embolic transport throughout the aortic arch is not well understood. The present study evaluated the aortic cannula’s outflow and orientation effect on emboli entering the aortic branch arteries. Methods: A simplified aortic computational model was anteriorly cannulated in the distal ascending aorta with a 21-French straight aortic cannula, and two orientations were analysed by injecting gaseous and solid emboli at pump flows 2, 3 and 5 L/minute. The first aortic cannula orientation (forward flow cannula) was directed towards the lesser curvature. The second aortic cannula orientation (rear flow cannula) was tilted slightly backwards by 15°, providing flow in the retrograde direction. Results: Forward flow cannula produced a primary arch flow, whereas rear flow cannula produced a secondary arch flow resulting in four times longer emboli arch resident times than forward flow cannula. The rear flow cannula had the highest percentage of gaseous emboli entering the brachiocephalic artery of 8%, 12% and 36% (at 2, 3 and 5 L/minute, respectively). Rear flow cannula provided a positive aortic branch arterial flow at all pump flows, whereas at forward flow cannula, the brachiocephalic artery experienced retrograde flows of −1.0% (3 L/minute) and −4.0% (5 L/minute), with the left common carotid −0.23% (5 L/minute). No significant number of solid emboli entered the aortic branch arteries. Conclusion: This numerical study illustrated distinct trajectory behaviours between gaseous and solid emboli where slight changes in aortic cannula orientation influenced idealised emboli direction with higher pump flows magnifying the effects.

Comparison of Blood Pressure Measured at the Aortic Cannula Sideport and within the Ascending Aorta after Cardiopulmonary Bypass

2003 ◽  
Vol 44 (1) ◽  
pp. 42
Author(s):  
Soon Eun Park ◽  
Keon Kang ◽  
Se Hun Park ◽  
Young Woo Cho ◽  
Je Kyoun Shin ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiopulmonary Bypass ◽  
Ascending Aorta ◽  
Aortic Cannula

scholarly journals Técnica del debranching híbrido tipo I del arco aórtico sin circulación extracorpórea

2019 ◽  
Vol 111 (4) ◽  
pp. 274-283
Author(s):  
Michel David ◽  
◽  
Raúl A. Borracci ◽  
Luis M. Ferreira ◽  
Patricio Giménez Ruiz ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Surgical Technique ◽  
Aortic Arch ◽  
Left Subclavian Artery ◽  
Ascending Aorta ◽  
Type I ◽  
Brachiocephalic Artery ◽  
Left Carotid Artery ◽  
Hybrid Treatment ◽  
Surgical Bypass

Aortic arch aneurysms represent a major challenge as the involvement of the supra-aortic vessels demands a complex surgical technique. Since the advent of endovascular aortic repair, hybrid treatment of aortic arch disease has emerged in recent years. The procedure consists of surgical bypass of the supra-aortic vessels followed by exclusion of the aneurysm with an endograft. This hybrid method is known as debranching and, briefly, consists in performing bypasses between the ascending aorta and the brachiocephalic artery, the left carotid artery and possibly the left subclavian artery without cardiopulmonary bypass, in order to advance an endograft to cover the entire lumen of the aneurysm. The aim of this paper is to describe the surgical technique of type I hybrid debranching without cardiopulmonary bypass and antegrade endograft delivery to treat aortic arch aneurysms.

Cannulating a Dissecting Aorta Using Ultrasound-Epiaortic and Transesophageal Guidance

2011 ◽  
Vol 14 (6) ◽  
pp. 373 ◽  
Author(s):  
Saina Attaran ◽  
Maria Safar ◽  
Hesham Zayed Saleh ◽  
Mark Field ◽  
Manoj Kuduvalli ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Aortic Dissection ◽  
Acute Aortic Dissection ◽  
False Lumen ◽  
Type A ◽  
Ascending Aorta ◽  
Type A Aortic Dissection ◽  
Complete Rupture

<p>Management of acute Stanford type A aortic dissection remains a major surgical challenge. Directly cannulating the ascending aorta provides a rapid establishment of cardiopulmonary bypass but consists of risks such as complete rupture of the aorta, false lumen cannulation, subsequent malperfusion and propagation of the dissection.</p><p>We describe a technique of cannulating the ascending aorta in patients with acute aortic dissection that can be performed rapidly in hemodynamically unstable patients under ultrasound-epiaortic and transesophageal (TEE) guidance.</p>

scholarly journals Model of thermal buoyancy in cavity-ventilated roof constructions

2021 ◽  
pp. 174425912098418
Author(s):  
Toivo Säwén ◽  
Martina Stockhaus ◽  
Carl-Eric Hagentoft ◽  
Nora Schjøth Bunkholt ◽  
Paula Wahlgren
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Numerical Study ◽  
Air Flow ◽  
Wind Pressure ◽  
Air Flow Rate ◽  
Test Set ◽  
Air Cavity ◽  
Thermal Buoyancy ◽  
The Impact

Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.

The impact of exogenous nitric oxide during cardiopulmonary bypass for cardiac surgery

Perfusion ◽  
2021 ◽  
pp. 026765912110148
Author(s):  
Joseph Mc Loughlin ◽  
Lorraine Browne ◽  
John Hinchion
Keyword(s):  
Nitric Oxide ◽  
Systematic Review ◽  
Cardiac Surgery ◽  
Cardiopulmonary Bypass ◽  
Troponin I ◽  
Length Of Hospital Stay ◽  
Cochrane Library ◽  
High Quality Research ◽  
Low Cardiac Output Syndrome ◽  
The Impact

Objectives: Cardiac surgery using cardiopulmonary bypass frequently provokes a systemic inflammatory response syndrome. This can lead to the development of low cardiac output syndrome (LCOS). Both of these can affect morbidity and mortality. This study is a systematic review of the impact of gaseous nitric oxide (gNO), delivered via the cardiopulmonary bypass (CPB) circuit during cardiac surgery, on post-operative outcomes. It aims to summarise the evidence available, to assess the effectiveness of gNO via the CPB circuit on outcomes, and highlight areas of further research needed to develop this hypothesis. Methods: A comprehensive search of Pubmed, Embase, Web of Science and the Cochrane Library was performed in May 2020. Only randomised control trials (RCTs) were considered. Results: Three studies were identified with a total of 274 patients. There was variation in the outcomes measures used across the studies. These studies demonstrate there is evidence that this intervention may contribute towards cardioprotection. Significant reductions in cardiac troponin I (cTnI) levels and lower vasoactive inotrope scores were seen in intervention groups. A high degree of heterogeneity between the studies exists. Meta-analysis of the duration of mechanical ventilation, length of ICU stay and length of hospital stay showed no significant differences. Conclusion: This systematic review explored the findings of three pilot RCTs. Overall the hypothesis that NO delivered via the CPB circuit can provide cardioprotection has been supported by this study. There remains a significant gap in the evidence, further high-quality research is required in both the adult and paediatric populations.

scholarly journals Numerical Simulation of the Impact of the Heat Source Position on Melting of a Nano-Enhanced Phase Change Material

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1425
Author(s):  
Tarek Bouzennada ◽  
Farid Mechighel ◽  
Kaouther Ghachem ◽  
Lioua Kolsi
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Numerical Study ◽  
Melting Rate ◽  
Heat Transfer Fluid ◽  
Commercial Code ◽  
Tube Position ◽  
The Impact ◽  
Change Material

A 2D-symmetric numerical study of a new design of Nano-Enhanced Phase change material (NEPCM)-filled enclosure is presented in this paper. The enclosure is equipped with an inner tube allowing the circulation of the heat transfer fluid (HTF); n-Octadecane is chosen as phase change material (PCM). Comsol-Multiphysics commercial code was used to solve the governing equations. This study has been performed to examine the heat distribution and melting rate under the influence of the inner-tube position and the concentration of the nanoparticles dispersed in the PCM. The inner tube was located at three different vertical positions and the nanoparticle concentration was varied from 0 to 0.06. The results revealed that both heat transfer/melting rates are improved when the inner tube is located at the bottom region of the enclosure and by increasing the concentration of the nanoparticles. The addition of the nanoparticles enhances the heat transfer due to the considerable increase in conductivity. On the other hand, by placing the tube in the bottom area of the enclosure, the liquid PCM gets a wider space, allowing the intensification of the natural convection.

scholarly journals Impact of Regular Physical Activity on Aortic Diameter Progression in Paediatric Patients with Bicuspid Aortic Valve

2021 ◽  
Author(s):  
Emanuele Monda ◽  
◽  
Adelaide Fusco ◽  
Alessandro Della Corte ◽  
Martina Caiazza ◽  
...  
Keyword(s):  
Physical Activity ◽  
Ascending Aorta ◽  
Regular Physical Activity ◽  
Aortic Diameter ◽  
Sinus Of Valsalva ◽  
Physically Active ◽  
The Impact ◽  
Aorta Diameter ◽  
Sedentary Subjects

AbstractPatients with bicuspid aortic valve (BAV) have an increased risk of aortic dilation and aortic dissection or rupture. The impact of physical training on the natural course of aortopathy in BAV patients remains unclear. The aim of this study was to evaluate the impact of regular physical activity on aortic diameters in a consecutive cohort of paediatric patients with BAV. Consecutive paediatric BAV patients were evaluated and categorized into two groups: physically active and sedentary subjects. Only the subjects with a complete 2-year follow-up were included in the study. To evaluate the potential impact of physical activity on aortic size, aortic diameters were measured at the sinus of Valsalva and mid-ascending aorta using echocardiography. We defined aortic diameter progression the increase of aortic diameter ≥ 10% from baseline. Among 90 BAV patients (11.5 ± 3.4 years of age, 77% males), 53 (59%) were physically active subjects. Compared to sedentary, physically active subjects were not significantly more likely to have > 10% increase in sinus of Valsalva (13% vs. 8%, p-value = 0.45) or mid-ascending aorta diameter (9% vs. 13%, p-value = 0.55) at 2 years follow-up, both in subjects with sinus of Valsalva diameter progression (3.7 ± 1.0 mm vs. 3.5 ± 0.8 mm, p-value = 0.67) and in those with ascending aorta diameter progression (3.0 ± 0.8 mm vs. 3.2 ± 1.3 mm, p-value = 0.83). In our paediatric cohort of BAV patients, the prevalence and the degree of aortic diameter progression was not significantly different between physically active and sedentary subjects, suggesting that aortic dilation is unrelated to regular physical activity over a 2-year period.

Persistent end-diastolic forward flow after pulmonary valve replacement in patients with repaired tetralogy of Fallot

2021 ◽  
Author(s):  
Yuji Tominaga ◽  
Masaki Taira ◽  
Takashi Kido ◽  
Tomomitsu Kanaya ◽  
Kanta Araki ◽  
...  
Keyword(s):  
Tetralogy Of Fallot ◽  
Valve Replacement ◽  
Pulmonary Valve ◽  
Pulmonary Valve Replacement ◽  
Right Atrial ◽  
Volume Index ◽  
Forward Flow ◽  
Repaired Tetralogy Of Fallot ◽  
Increased Risk ◽  
The Impact

Abstract OBJECTIVES The clinical significance of persistent end-diastolic forward flow (EDFF) after pulmonary valve replacement (PVR) remains unclear in patients with repaired tetralogy of Fallot. This study aimed to identify the characteristics of these patients and the impact of persistent EDFF on outcomes. METHODS Of 46 consecutive patients who underwent PVR for moderate to severe pulmonary regurgitation between 2003 and 2019, 23 (50%) did not show EDFF before PVR [group (−)]. In the remaining 23 patients with EDFF before PVR, EDFF was diminished after PVR in 13 (28%) [group (+, −)] and persisted in 10 (22%) [group (+, +)]. The following variables were compared between these 3 groups: (i) preoperative right ventricular (RV) and right atrial volumes measured by magnetic resonance imaging, haemodynamic parameters measured by cardiac catheterization and the degree of RV myocardial fibrosis measured by RV biopsy obtained at PVR and (ii) the post-PVR course, development of atrial arrhythmia and need for intervention. RESULTS A high RV end-diastolic pressure, a greater right atrial volume index and a greater RV end-systolic volume index before PVR and a high degree of RV fibrosis were significantly associated with persistent EDFF 1 year after PVR. Persistent EDFF was a significant risk factor for postoperative atrial tachyarrhythmia, and catheter ablation and pacemaker implantation were required more frequently in these patients. CONCLUSIONS Persistent EDFF after PVR could predict a worse prognosis, especially an increased risk of arrhythmia. Close follow-up is required in patients with persistent EDFF for early detection of arrhythmia and prompt reintervention if necessary. Clinical trial registration number Institutional review board of Osaka University Hospital, number 16105

OPTIMAL REINSURANCE FROM THE VIEWPOINTS OF BOTH AN INSURER AND A REINSURER UNDER THE CVAR RISK MEASURE AND VAJDA CONDITION

2021 ◽  
pp. 1-29
Author(s):  
Yanhong Chen
Keyword(s):  
Loss Function ◽  
Value At Risk ◽  
Numerical Study ◽  
Risk Measure ◽  
Convex Combination ◽  
Weighting Factor ◽  
Loss Functions ◽  
Conditional Value At Risk ◽  
Optimal Reinsurance ◽  
The Impact

ABSTRACT In this paper, we study the optimal reinsurance contracts that minimize the convex combination of the Conditional Value-at-Risk (CVaR) of the insurer’s loss and the reinsurer’s loss over the class of ceded loss functions such that the retained loss function is increasing and the ceded loss function satisfies Vajda condition. Among a general class of reinsurance premium principles that satisfy the properties of risk loading and convex order preserving, the optimal solutions are obtained. Our results show that the optimal ceded loss functions are in the form of five interconnected segments for general reinsurance premium principles, and they can be further simplified to four interconnected segments if more properties are added to reinsurance premium principles. Finally, we derive optimal parameters for the expected value premium principle and give a numerical study to analyze the impact of the weighting factor on the optimal reinsurance.

Sign in / Sign up

Export Citation Format

Share Document